Semiconductor Device and Method for Forming Passive Circuit Elements with Through Silicon Vias to Backside Interconnect Structures

ABSTRACT

A semiconductor wafer contains a substrate having a plurality of active devices formed thereon. An analog circuit is formed on the substrate. The analog circuit can be an inductor, metal-insulator-metal capacitor, or resistor. The inductor is made with copper. A through substrate via (TSV) is formed in the substrate. A conductive material is deposited in the TSV in electrical contact with the analog circuit. An under bump metallization layer is formed on a backside of the substrate in electrical contact with the TSV. A solder material is deposited on the UBM layer. The solder material is reflowed to form a solder bump. A wire bond is formed on a top surface of the substrate. A redistribution layer is formed between the TSV and UBM. The analog circuit electrically connects through the TSV to the solder bump on the back side of the substrate.

FIELD OF THE INVENTION

The present invention relates in general to semiconductor devices and,more particularly, to a semiconductor device with integrated passivecircuit elements interconnected to backside solder bumps.

BACKGROUND OF THE INVENTION

Semiconductor devices are found in many products in the fields ofentertainment, communications, networks, computers, and householdmarkets. Semiconductor devices are also found in military, aviation,automotive, industrial controllers, and office equipment. Thesemiconductor devices perform a variety of electrical functionsnecessary for each of these applications.

The manufacture of semiconductor devices involves formation of a waferhaving a plurality of die. Each semiconductor die contains hundreds orthousands of transistors and other active and passive devices performinga variety of electrical functions. For a given wafer, each die from thewafer typically performs the same electrical function. Front-endmanufacturing generally refers to formation of the semiconductor deviceson the wafer. The finished wafer has an active side containing thetransistors and other active and passive components. Back-endmanufacturing refers to cutting or singulating the finished wafer intothe individual die and then packaging the die for structural support andenvironmental isolation.

One goal of semiconductor manufacturing is to produce a package suitablefor faster, reliable, smaller, and higher-density integrated circuits(IC) at lower cost. Flip chip packages or wafer level chip scalepackages (WLCSP) are ideally suited for ICs demanding high speed, highdensity, and greater pin count. Flip chip style packaging involvesmounting the active side of the die facedown toward a chip carriersubstrate or printed circuit board (PCB). The electrical and mechanicalinterconnect between the active devices on the die and conduction trackson the carrier substrate is achieved through a solder bump structurecomprising a large number of conductive solder bumps or balls. Thesolder bumps are formed by a reflow process applied to solder materialdeposited on contact pads which are disposed on the semiconductorsubstrate. The solder bumps are then soldered to the carrier substrate.The flip chip semiconductor package provides a short electricalconduction path from the active devices on the die to the carriersubstrate in order to reduce signal propagation, lower capacitance, andachieve overall better circuit performance.

In many applications, it is desirable to form passive circuit elements,including inductors, resistors, and capacitors, on the semiconductorwafer. The inductor and capacitor allows the IC to perform reactivecircuit functions without using external circuit components. The passivecircuit elements, particularly inductors, occupy significant area on thedie. The inductors are typically formed as coiled or wound metal layerson the surface of the substrate which consumes a large area. The diemust also accommodate interconnect structures, such as solder bumps,which also occupy significant space. The demand for smaller die withhigh feature density is challenging to achieve when taking into accountthe interconnect requirements.

A need exists to integrate passive circuit elements and interconnectstructures with the demand for smaller and denser semiconductor die.

SUMMARY OF THE INVENTION

In one embodiment, the present invention is a method of making asemiconductor device comprising the steps of providing a substratehaving a plurality of active devices formed thereon, forming an analogcircuit on the substrate, forming a through substrate via (TSV) in thesubstrate, depositing conductive material in the TSV in electricalcontact with the analog circuit, forming an under bump metallization(UBM) layer on a backside of the substrate in electrical contact withthe conductive material in the TSV, depositing solder material on theUBM layer, and reflowing the solder material to form a solder bump. Theanalog circuit electrically connects through the TSV to the solder bumpon the back side of the substrate.

In another embodiment, the present invention is a method of making asemiconductor device comprising the steps of providing a substrate,forming a passive device on the substrate, and forming a via through thesubstrate. The via containing conductive material is in electricalcontact with the passive device. The method further includes the step offorming an interconnect structure on a backside of the substrate inelectrical contact with the conductive material in the via. The passivedevice electrically connects through the via to the interconnectstructure on the back side of the substrate.

In another embodiment, the present invention is a method of making asemiconductor device comprising the steps of providing a substrate,forming a passive device on the substrate, forming a via through thesubstrate, depositing conductive material in the via, and forming aninterconnect structure on a backside of the substrate in electricalcontact with the conductive material in the via.

In another embodiment, the present invention is a semiconductor devicecomprising a substrate, a passive device formed on the substrate, and avia formed through the substrate. The via contains conductive materialin electrical contact with the passive device. An interconnect structureis formed on a backside of the substrate in electrical contact with thevia. The passive device electrically connects through the via to theinterconnect structure on the back side of the substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flip chip semiconductor device with solder bumps providingelectrical interconnect between an active area of the die and a chipcarrier substrate;

FIGS. 2 a-2 f illustrate a process of forming passive circuit elementswith through silicon vias to backside solder bumps on the semiconductorpackage;

FIG. 3 illustrates a semiconductor package with passive circuit elementsand backside RDL to solder bumps;

FIG. 4 illustrates a semiconductor package with passive circuit elementsinterconnected to topside wire bond pads and through silicon vias tobackside solder bumps;

FIG. 5 illustrates a semiconductor package with passive circuit elementsinterconnected to other semiconductor packages; and

FIGS. 6 a-6 e illustrate an alternate process of forming passive circuitelements with through silicon vias to backside solder bumps on thesemiconductor package.

DETAILED DESCRIPTION OF THE DRAWINGS

The present invention is described in one or more embodiments in thefollowing description with reference to the Figures, in which likenumerals represent the same or similar elements. While the invention isdescribed in terms of the best mode for achieving the invention'sobjectives, it will be appreciated by those skilled in the art that itis intended to cover alternatives, modifications, and equivalents as maybe included within the spirit and scope of the invention as defined bythe appended claims and their equivalents as supported by the followingdisclosure and drawings.

The manufacture of semiconductor devices involves formation of a waferhaving a plurality of die. Each die contains hundreds or thousands oftransistors and other active and passive devices performing one or moreelectrical functions. For a given wafer, each die from the wafertypically performs the same electrical function. Front-end manufacturinggenerally refers to formation of the semiconductor devices on the wafer.The finished wafer has an active side containing the transistors andother active and passive components. Back-end manufacturing refers tocutting or singulating the finished wafer into the individual die andthen packaging the die for structural support and/or environmentalisolation.

A semiconductor wafer generally includes an active surface havingsemiconductor devices disposed thereon, and a backside surface formedwith bulk semiconductor material, e.g., silicon. The active side surfacecontains a plurality of semiconductor die. The active surface is formedby a variety of semiconductor processes, including layering, patterning,doping, and heat treatment. In the layering process, semiconductormaterials are grown or deposited on the substrate by techniquesinvolving thermal oxidation, nitridation, chemical vapor deposition,evaporation, and sputtering. Photolithography involves the masking ofareas of the surface and etching away undesired material to formspecific structures. The doping process injects concentrations of dopantmaterial by thermal diffusion or ion implantation.

Flip chip semiconductor packages and wafer level packages (WLP) arecommonly used with integrated circuits (ICs) demanding high speed, highdensity, and greater pin count. Flip chip style semiconductor device 10involves mounting an active area 12 of die 14 facedown toward a chipcarrier substrate or printed circuit board (PCB) 16, as shown in FIG. 1.Active area 12 contains active and passive devices, conductive layers,and dielectric layers according to the electrical design of the die.Analog circuits may be created by the combination of one or more passivedevice formed within active area 12 and electrically interconnected. Forexample, an analog circuit may include one or more inductor, capacitorand resistor formed within active area 12. The electrical and mechanicalinterconnect is achieved through a solder bump structure 20 comprising alarge number of individual conductive solder bumps or balls 22. Thesolder bumps are formed on bump pads or interconnect sites 24, which aredisposed on active area 12. The bump pads 24 connect to the activecircuits by conduction tracks in active area 12. The solder bumps 22 areelectrically and mechanically connected to contact pads or interconnectsites 26 on carrier substrate 16 by a solder reflow process. The flipchip semiconductor device provides a short electrical conduction pathfrom the active devices on die 14 to conduction tracks on carriersubstrate 16 in order to reduce signal propagation, lower capacitance,and achieve overall better circuit performance.

FIG. 2 a illustrates semiconductor wafer 28 having a substrate 30 madeof silicon or other bulk semiconductor material. Trenches or vias 34 and36 are cut into substrate 30 using a deep reactive ion etch (DRIE)process or silicon wet etching with potassium hydroxide (KOH) process.Trenches 34 and 36 will become through substrate vias (TSV) in laterstages. An insulating layer 38 is deposited by chemical vapor deposition(CVD) over substrate 30. The insulating layer 38 follows the contour ofthe substrate and provides a via liner for trenches 34 and 36. Theinsulating layer 38 can be made with silicon dioxide (SiO2), siliconoxynitride (SiON), silicon nitride (SixNy), tantalum pentoxide (Ta2O5),zirconium (Zr) oxide, or other material having dielectric properties.The thickness of insulating layer 38 ranges from 500 angstroms (Å) to 30micrometers (μm) with a typical value of about 1000 Å.

In FIG. 2 b, an electrically conductive layer 40 is deposited andpatterned on insulating layer 38. Conductive layer 40 can be made withaluminum (Al), Al alloy, copper (Cu), nickel (Ni), gold (Au), silver(Ag), or other electrically conductive material. Cu is typically used inconjunction with an adhesion layer and barrier layer. Conductive layer40 can have multiple layers such as titanium (Ti)/titanium nitride(TiN)/Al/TiN. The deposition of conductive layer 40 uses a physicalvapor deposition (PVD), CVD, evaporation, electrolytic plating, orelectroless plating process. The conductive layers 40 can beelectrically common or electrically isolated depending on theconnectivity of the individual devices formed on substrate 30. Thepattern of conductive layer 40 in vias 34 and 36 is optional.

A resistive layer 42, noted as resistive layers 42 a and 42 b, isdeposited and patterned on insulating layer 38 and connected toconductive layer 40 to form a resistor. Alternatively, resistive layer42 can be connected through plating layer 50 and Cu layer 54 to form aresistor, see FIG. 2 c. Resistive layer 42 b is patterned betweenconductive layer 40 and insulating layer 46 to suppress the Hillockgrowth. Resistive layer 42 is made with silicide, doped poly silicon,tantalum nitride (TaN), nickel chromium (NiCr), or TiN having a sheetresistivity up to about 100 ohm/square. The deposition of resistivelayer 42 may involve PVD or CVD with a thickness ranging from 200-5000Å.

An insulating layer 46 is deposited and patterned on resistive layer 42b. The insulating layer 46 may cover other circuit regions forinsulation purposes. The insulating layer 46 can be made with SiO2,SixNy, SiON, Ta2O5, Zr oxide, or other dielectric material. Thedeposition of insulating layer 46 may involve PVD or CVD.

A passivation layer 48 is formed over the structure created in FIGS. 2a-2 b for structural support and electrical isolation. Passivation layer48 can be made with SiO2, SixNy, SiON, polyimide (PI), benzocyclobutene(BCB), polybenzoxazole (PBO), or other insulating material. A portion ofpassivation layer 48 is removed using a mask-defined photolithographyprocess to expose conductive layers 40 and insulating layers 38 and 46.

In FIG. 2 c, a metal plating layer 50, e.g. Cu plating, is deposited andpatterned with thick photoresist 52. The plating layer 50 has anadhesion layer and seed layer. The adhesion layer can be made with Ti,TiW, Ta/TaN, or Cr. The seed layer is typically Cu. A layer ofphotoresist 52 is patterned over plating layer 50 for Cu layer 54. Culayer 54 can be deposited as a conformal coating over trenches 34 and36. Alternatively, Cu layer 54 can be a via fill process which depositsCu into vias 34 and 36. Cu layer 54 can be used to form interconnectionas well as inductor wings or transmission lines. The inductor wings areformed together with TSV metal deposition through Cu plating. The Cumaterial in trenches 34 and 36 can be formed at the same time as Culayer 54 and 54 a on passivation layer 48. Alternately, a dual platingof the Cu layers fills trenches 34 and 36 and forms Cu layer 54 a atdifferent times. The optional conductive layer 40 in vias 34 and 36improves metal step coverage and Cu fill process in the vias. Cu layers54 can be electrically common or electrically isolated depending on theconnectivity of the individual devices formed on substrate 30.

In FIG. 2 d, photoresist 52 is removed. A portion of plating layer 50 isremoved by etching. Passivation layer 58 is coated over the structureformed in FIGS. 2 a-2 c for structural support and electrical isolation.Passivation layer 58 can be made with SiO2, SixNy, SiON, PI, BCB, PBO,epoxy, or other insulating material.

In FIG. 2 e, semiconductor wafer 28 is back grinded to expose TSV 34 and36. Accordingly, conductive vias 34 and 36 pass through siliconsubstrate 30. A passivation layer 60 is deposited and patterned on thebackside of semiconductor wafer 28. Passivation layer 60 can be madewith SiO2, SixNy, SiON, PI, BCB, PBO, epoxy, or other insulatingmaterial. An under bump metallization (UBM) 62 is deposited andpatterned to electrically contact Cu layer 54 in TSV 34 and 36. UBMs 62can be made with Ti, Ni, NiV, Cu, or Cu alloy. UBMs 62 can be a multiplemetal stack with adhesion layer, barrier layer, and wetting layer. Theadhesion layer is made with Ti, Cr, Al, TiW, or titanium nitride (TiN).The barrier layer can be made with Ni, NiV, CrCu, or TiW. The wettinglayer can be made with Cu, Au, or Ag. The exposed TSV 34 and 36 can beused for alignment of UBMs 62. Alternatively, a back side alignment(BSA) infrared (IR) alignment can be used to form UBMs 62.

An electrically conductive solder material is deposited over UBMs 62through an evaporation, electrolytic plating, electroless plating, balldrop, or screen printing process. The solder material can be any metalalloy or electrically conductive material, e.g., Sn, lead (Pb), Ni, Au,Ag, Cu, bismuthinite (Bi), and alloys thereof. The solder material istypically lead-free such as Sn96.5Ag3.5. The solder material is reflowedby heating the conductive material above its melting point to formspherical balls or bumps 66. In some applications, solder bumps 66 arereflowed a second time to improve electrical contact to UBMs 62. UBMs 62and solder bumps 66 represent one type of interconnect structure.

In FIG. 2 f, an optional polymer glue layer 70 is applied overpassivation layer 58. Chip carrier 72 is bonded to semiconductor wafer28 with polymer glue layer 70. Alternatively, backgrinding tape orpermanent molding compound is applied without carrier 72. When permanentmolding compound is applied, passivation layer 58 can be optional. Thebackgrinding tape or polymer glue with carrier 72 is removed before orafter dicing. Alternatively, the glue and carrier may remain permanentlyattached and become part of the die.

The passive circuit elements, such as resistors, inductors, andcapacitors, occupy a significant portion of the limited space on thesurface of substrate 30. The interconnect structures like UBMs 62 andsolder bumps 66 are disposed on the backside of the die. Semiconductorpackage 68 uses many TSVs like 34 and 36 to electrically connect thepassive circuit elements on the topside of the die through UBMs 62 tosolder bumps 66 on the backside of the die to provide for greater use ofdie area and improve reliability.

The semiconductor device in FIG. 2 e has a number of passive circuitelements. Cu layer 54 a represents a cross-sectional view of an inductorcoiled on the surface of substrate 30. The inductor is formed as coiledor wound metal layers on the surface of the substrate. The conductivelayers 40 and Cu layers 54 can be electrically common or electricallyisolated to connect the passive circuit elements according to thedesired circuit function. For example, the portion of CU layer 54overlying TSVs 34 and 36 can electrically contact Cu layer 54 a toconnect both ends of the inductor formed by Cu layer 54 a through UBMs62 to solder bumps 66 under TSVs 34 and 36, respectively.

In a similar manner, the resistive layer 42 a also provides a passivecircuit element, i.e., a resistor connected between conductive layers40. The portion of Cu layers 54 overlying conductive layers 40 betweenresistive layer 42 a can electrically contact Cu layers 54 overlyingTSVs 34 and 36 to connect both ends of the resistor formed by resistivelayer 42 a through UBMs 62 to solder bumps 66 under TSV 34 and 36,respectively.

In another example, the combination of conductive layer 40, resistivelayer 42 b, insulating layer 46, conductive layer 50, and Cu layer 54constitute a passive circuit, i.e., a resistor in series with ametal-insulator-metal (MIM) capacitor. The portion of Cu layer 54 incontact with conductive layer 40 under resistive layer 42 b canelectrically contact Cu layer 54 overlying TSV 34. The portion of Culayer 54 overlying insulating layer 46 can electrically contact Cu layer54 overlying TSV 36.

Accordingly, TSVs 34 and 36 allow the passive circuit elements to beplaced on the topside of the die and to be electrically connected to theinterconnect structures, which are disposed on the backside of the die.The placement of passive circuit elements on the topside of substrate 30and the interconnect structures on the backside of substrate 30 providesfor greater use of die area and improves reliability. The TSVs providefor electrical connection between the topside passive circuit elementsand the backside interconnect structures. The inductor and MIM capacitorallow the semiconductor device to perform reactive circuit functionswithout using external circuit components.

FIG. 3 illustrates an alternate embodiment of the semiconductor package.Redistribution layers (RDL) 74 and 80 are formed over passivation layer60. In one embodiment, RDLs 74 and 80 may include a wetting layer,barrier layer, and adhesive layer. RDLs 74 and 80 provide electricalcontact between the Cu material in TSV 34 and solder bumps 78 and 82,respectively. RDLs 74 and 80 can be made with Al, aluminum copper alloy(AlCu), Cu, or Cu alloy with an adhesion and barrier layers. Theadhesion layer can be Ti, TiN, TiW, Cr, or Ta. The barrier layer can beNiV, TaN, TiW, or CrCu. RDLs 74 and 80 operate as an intermediateconduction layer to route electrical signals from solder bumps 78 and 82to various areas of the die, including active and passive circuits, andprovides various electrical interconnect options during integration ofsemiconductor package 86. RDLs 74 and 80 provide routing options torelocate solder bumps 78 and 82 away from TSV 34 and 36. A passivationlayer 84 is formed over RDLs 74 and 80 and passivation layer 60.

FIG. 4 illustrates an alternate embodiment of the semiconductor package.A TSV 34 is formed on the left side of the semiconductor package usingthe steps described in FIGS. 2 a-2 f. A wire bonding pad 90 is formed onthe right side of semiconductor package.

FIG. 5 illustrates another embodiment of the semiconductor package. Inthis embodiment, multiple TSVs 34 and 36 and solder bumps 66 areprovided on both ends of the semiconductor package. Passive devicesand/or analog circuits 110 are mounted on passivation layer 58 withunderfill material 114 and are electrically connected by contact pad112. Semiconductor die 116 is mounted to passivation layer 58 withunderfill material 118 and is electrically connected to Cu layers 54with solder bumps 120. Semiconductor die 122 is mounted to passivationlayer 58 with underfill material 124 and is electrically connected to Culayers 54 with solder bumps 126. Molding compound 128 or other compositepolymer materials with proper coefficient of thermal expansion (CTE) isdeposited over the structures formed on FIG. 5. Topside grinding may beused to get a flatter surface.

FIG. 6 a illustrates semiconductor wafer 129 having a substrate 130 madeof silicon or other bulk semiconductor material. Trenches or vias 134and 136 are cut into substrate 130 using wet silicon etching processsuch as KOH. Trenches 134 and 136 will become TSVs in later stages. Aninsulating layer 138 is deposited by CVD over substrate 130, followingthe contour of the substrate and providing a via liner for trenches 134and 136. The insulating layer 138 can be made with SiO2, SiON, SixNy,Ta2O5, ZrO, or other material having dielectric properties. Thethickness of insulating layer 138 ranges from 500 Å to 30 μm with atypical thickness of about 1000 Å.

In FIG. 6 b, an electrically conductive layer 140 is deposited andpatterned on insulating layer 138. Conductive layer 140 can be made withAl, Al alloy, Ti/TiN/Al/TiN, Cu, Ni, Au, Ag, or other electricallyconductive material. The pattern of conductive layer 140 in vias 134 and136 is optional. The deposition of conductive layer 140 uses a PVD, CVD,evaporation, electrolytic plating, electroless plating, or screenprinting process. The conductive layers 140 can be electrically commonor electrically isolated depending on the connectivity of the individualdevices formed on substrate 130.

A resistive layer 142, noted as resistive layers 142 a and 142 b, isdeposited and patterned on insulating layer 138 and conductive layer140. Resistive layer 142 is made with silicide, doped poly Si, TaN, orNiCr having a resistivity up to about 100 ohm/square. The deposition ofresistive layer 142 may involve PVD or CVD.

An insulating layer 146 is patterned and deposited on resistive layer142 b. The insulating layer 146 can be made with SiO2, SixNy, SiON,Ta2O5, Zr2O5, or other dielectric material. The deposition of insulatinglayer 146 may involve PVD or CVD with typical thickness of 200-4000 Å.

A passivation layer 148 is formed over the structure created in FIGS. 6a-6 b for structural support and electrical isolation. Passivation layer148 can be made with SiO2, SixNy, SiON, PI, BCB, PBO, or otherinsulating material. A portion of passivation layer 148 is removed usinga mask-defined photolithography process to expose conductive layers 140and insulating layers 138 and 146.

In FIG. 6 c, a metal plating 150, e.g. Cu plating, is deposited andpatterned with thick photo resist 152. The plating layer 150 has anadhesion layer and seed layer. The adhesion layer can be made with Ti,TiW, Ta/TaN, or Cr. The seed layer is typically Cu. A layer ofphotoresist 152 patterns plating layer 150 for Cu layer 154. Cu layer154 can also be deposited as a conformal coating over trenches 134 and136. Alternatively, Cu layer 154 can be formed via a fill process whichdeposits Cu into vias 134 and 136. Cu layer 154 can be used to forminterconnection as well as inductor wings or transmission lines. Theinductor wings are formed together with TSV metal deposition through Cuplating. The Cu layer 154 is a conductive material deposited in trenches134 and 136 as well as other locations on the surface of substrate 130to form conductive layers and passive devices or analog circuits. The Cumaterial in trenches 134 and 136 can be formed at the same time as Culayer 154 and 154 a on passivation layer 148. Alternately, a dualplating of the Cu layers fills trenches 134 and 136 and forms Cu layer154 a at different times. The Cu plating rate in trenches 134 and 136improves with conductive layer 140. Cu layers 154 can be electricallycommon or electrically isolated depending on the connectivity of theindividual devices formed on substrate 130.

In FIG. 6 d, photoresist 152 is removed. A portion of Cu plating layer150 is removed by etching. Passivation layer 158 is coated over thestructure formed in FIGS. 6 a-6 c for structural support and electricalisolation. Passivation layer 158 can be made with SiO2, SixNy, SiON, PI,BCB, PBO, or other insulating material.

In FIG. 6 e, semiconductor wafer 170 is back grinded to expose TSV 134and 136. Accordingly, conductive vias 134 and 136 pass through siliconsubstrate 130. A passivation layer 160 is deposited and patterned on thebackside of semiconductor wafer 170. Passivation layer 160 can be madewith SiO2, SixNy, SiON, PI, BCB, PBO, epoxy, or other insulatingmaterial. A UBM 162 is deposited and patterned to electrically contactCu layer 154 in TSV 134 and 136. UBMs 162 can be made with Ti, Ni, NiV,Cu, or Cu alloy. UBMs 162 can be a multiple metal stack with adhesionlayer, barrier layer, and wetting layer. The adhesion layer is made withTi, Cr, Al, TiW, or titanium nitride (TiN). The barrier layer can bemade with Ni, NiV, CrCu, or TiW. The wetting layer can be made with Cu,Au, or Ag. The exposed TSV 134 and 136 can be used for alignment of UBMs162. Alternatively, a BSA/IR alignment can be used to form UBMs 162.

An electrically conductive solder material is deposited over UBMs 162through an evaporation, electrolytic plating, electroless plating, balldrop, or screen printing process. The solder material can be any metalor metal alloy or electrically conductive material, e.g., Sn, Pb, Ni,Au, Ag, Cu, Bi, and alloys thereof. The solder material is reflowed byheating the conductive material above its melting point to formspherical balls or bumps 166. In some applications, solder bumps 166 arereflowed a second time to improve electrical contact to UBMs 162. UBMs162 and solder bumps 166 represent one type of interconnect structure.

The passive circuit elements, such as resistors, inductors, andcapacitors, occupy a significant portion of the limited space on thesurface of substrate 130. The interconnect structures like UBMs 162 andsolder bumps 166 are disposed on the backside of the die. Semiconductorpackage 170 uses many TSVs like 134 and 136 to electrically connect thepassive circuit elements on the topside of the die through UBMs 162 tosolder bumps 166 on the backside of the die to provide for greater useof the die area and improve reliability.

The semiconductor device in FIG. 6 e has a number of passive circuitelements. Cu layer 154 a represents a cross-sectional view of aninductor coiled on the surface of substrate 130. The inductor is formedas coiled or wound metal layers on the surface of the substrate. Theconductive layers 140 and Cu layers 154 can be electrically common orelectrically isolated to connect the passive circuit elements accordingto the desired circuit function. For example, the portion of CU layer154 overlying TSVs 134 and 136 can electrically contact Cu layer 154 ato connect both ends of the inductor formed by Cu layer 154 a throughUBMs 162 to solder bumps 166 under TSVs 134 and 136, respectively.

In a similar manner, the resistive layer 142 a also provides a passivecircuit element, i.e., a resistor connected between conductive layers140. The portion of Cu layers 154 overlying conductive layers 140between resistive layer 142 a can electrically contact Cu layers 154overlying TSVs 134 and 136 to connect both ends of the resistor formedby resistive layer 142 a through UBMs 162 to solder bumps 166 under TSV134 and 136, respectively.

In another example, the combination of conductive layer 140, resistivelayer 142 b, insulating layer 146, conductive layer 150, and Cu layer154 constitute a passive circuit, i.e., a resistor in series with a MIMcapacitor. The portion of Cu layer 154 in contact with conductive layer140 under resistive layer 142 b electrically contacts Cu layer 154overlying TSV 134. The portion of Cu layer 154 overlying insulatinglayer 146 electrically contacts Cu layer 154 overlying TSV 136.

Accordingly, TSVs 134 and 136 allows the passive circuit elements to beplaced on the topside of the die to be electrically connected to theinterconnect structures, which are disposed on the backside of the die.The placement of passive circuit elements on the topside of substrate130 and the interconnect structures on the backside of substrate 130provides for greater use of die area and improves reliability. The TSVsprovide for electrical connection between the topside passive circuitelements and the backside interconnect structures. The inductor and MIMcapacitor allow the semiconductor device to perform reactive circuitfunctions without using external circuit components.

While one or more embodiments of the present invention have beenillustrated in detail, the skilled artisan will appreciate thatmodifications and adaptations to those embodiments may be made withoutdeparting from the scope of the present invention as set forth in thefollowing claims

1. A method of making a semiconductor device, comprising: providing asubstrate; forming an analog circuit on the substrate; forming a throughsubstrate via (TSV) in the substrate; depositing conductive material inthe TSV in electrical contact with the analog circuit; forming aninsulation layer over a back surface of the substrate; forming an underbump metallization (UBM) layer on a backside of the substrate inelectrical contact with the conductive material in the TSV; depositingsolder material on the UBM layer; and reflowing the solder material toform a solder bump, wherein the analog circuit electrically connectsthrough the TSV to the solder bump on the back side of the substrate. 2.The method of claim 1, further including forming a plurality of activedevices on the substrate.
 3. The method of claim 1, further includingforming a redistribution layer between the TSV and UBM.
 4. The method ofclaim 1, wherein the analog circuit includes an inductor,metal-insulator-metal capacitor, or resistor.
 5. The method of claim 4,wherein the analog circuit includes an inductor that is made with copperand is deposited at approximately the same time as the deposition ofconductive material in the TSV.
 6. The method of claim 1, furtherincluding forming a wire bond on a top surface of the substrate.
 7. Themethod of claim 1, further including depositing polymer glue over thesubstrate and bonding a chip carrier to the polymer glue.
 8. A method ofmaking a semiconductor device, comprising: providing a substrate;forming a passive device on the substrate; forming a via through thesubstrate, the via containing conductive material in electrical contactwith the passive device; and forming an interconnect structure on abackside of the substrate in electrical contact with the conductivematerial in the via, wherein the passive device electrically connectsthrough the via to the interconnect structure on the back side of thesubstrate.
 9. The method of claim 8, wherein forming an interconnectstructure on a backside of the substrate includes: forming an under bumpmetallization layer in electrical contact with the via; and forming asolder bump on the under bump metallization layer.
 10. The method ofclaim 8, further including forming a redistribution layer between thevia and interconnect structure.
 11. The method of claim 8, wherein thepassive device is an inductor.
 12. The method of claim 11, wherein theinductor is made with copper.
 13. The method of claim 8, wherein thepassive device is a metal-insulator-metal capacitor.
 14. The method ofclaim 8, wherein the passive device is a resistor.
 15. The method ofclaim 8, further including forming a wire bond on a top surface of thesubstrate.
 16. A method of making a semiconductor device, comprising:providing a substrate; forming a passive device on the substrate;forming a via through the substrate; depositing conductive material inthe via; and forming an interconnect structure on a backside of thesubstrate in electrical contact with the conductive material in the via.17. The method of claim 16, wherein forming an interconnect structure ona backside of the substrate includes: forming an under bumpmetallization layer in electrical contact with the via; and forming asolder bump on the under bump metallization layer.
 18. The method ofclaim 16, wherein the passive device is in electrical contact with theconductive material in the via.
 19. The method of claim 16, furtherincluding forming a redistribution layer between the via andinterconnect structure.
 20. The method of claim 16, wherein the passivedevice is an inductor, capacitor, or resistor.
 21. A semiconductordevice, comprising: a substrate; a passive device formed on thesubstrate; a via formed through the substrate, the via containingconductive material in electrical contact with the passive device; andan interconnect structure on a backside of the substrate in electricalcontact with the via, wherein the passive device electrically connectsthrough the via to the interconnect structure on the back side of thesubstrate.
 22. The semiconductor device of claim 21, wherein theinterconnect structure includes: an under bump metallization inelectrical contact with the conductive material in the via; and a solderbump formed on the under bump metallization.
 23. The semiconductordevice of claim 21, further including a redistribution layer formedbetween the via and interconnect structure.
 24. The semiconductor deviceof claim 21, wherein the passive device is an inductor, capacitor, orresistor.
 25. The semiconductor device of claim 21, further including awire bond formed on a top surface of the substrate.